Today's hair conditioners almost universally comprise high levels of high melting point fatty compounds, the most common of which are C16 to C18 fatty alcohols. These high melting point fatty compounds are employed as structuring agents wherein they are combined with one or more surfactants and an aqueous carrier to form a gel network. The gel network increases the viscosity and yield point which facilitates the dispensing of the conditioner from a bottle or tube and the subsequent distribution and spreading of the product through the hair by the consumer. The structuring of the product via gel network also enables incorporation of silicones, perfumes and oils in the form of an oil-in-water emulsion that is phase stable. These silicones and oils are intended to be deposited on the hair to provide the primary hair conditioning benefits including wet and dry combing friction reduction and hair manageability etc.
However, today's gel network hair conditioners lead to excessive co-deposits of the high melting point fatty compound on the hair over multiple cycles. Additionally, the deposited high melting point fatty compounds build-up on hair over multiple cycles and lead to significant waxy build-up on hair and hair weigh down. Indeed, one of the major consumer complaints with hair conditioners is waxy residue which makes hair look greasy or feel heavy. Many current gel network hair conditioners deposit up to 10 times more high melting point fatty compounds (fatty alcohols) than silicone or oil after approximately 10 treatment cycles in technical testing. While not being bound to theory, this is hypothesized to be due to the ˜10× greater concentration of high melting point weight fatty compounds in the product relative to the silicone or oil. Such a high level of melting point fatty compounds (fatty alcohols) may be required to produce a shelf stable gel network with sufficient structuring for consumer acceptable viscosity and rheology.
Described herein is a concentrated hair care composition that enables new product opportunities and consumer benefits by addressing the current disadvantages associated with gel network conditioners. It has been found that concentrated and ultra-low viscosity hair conditioner compositions can be delivered to the hair in foamed form with lower dosage (due to lower foam density). These inventive compositions are concentrated to enable sufficient dosage from a foam delivery form while also eliminating the need for high melting point fatty compounds or other “insoluble” structurants that can lead to significant co-deposits (from wax structured to gas structured), build-up and weigh down of hair. The inventive compositions are also nano-emulsions to help enable shelf stability at the lower viscosities required for foaming The net result has been a step change improvement in silicone deposition purity versus today's rinse-off products and an improvement in technical performance benefits from such a more pure and transparent deposited silicone layer. These benefits include multicycle hair conditioning without hair weigh down, durable conditioning, reduced hair dye fade, and increased color vibrancy.
Nanoemulsion technology development is hindered by complex stability issues that emerge when droplet sizes are driven to the nanoscale. This may be especially problematic in the presence of higher levels of perfume oils which may be required for such a concentrated product. The concentrated hair care composition described herein is therefore also focused on improved stability via the development of a specific emulsifier system.